Properties of mixed structures resulting from quenching

1. The use of partial austempering (with formation of≥70% bainite) as a final heat treatment and subsequent electrotempering in place of complete quenching with tempering produces a good combination of strength and ductile properties of steels 60 and 80 and increases the productivity of the heat treatment by 35–40%. 2. The optimal final treatment for steels 60 and 80 is as follows: austenitizing at 950° (for steel 60) and 900° (for steel 80) for 1200 sec, partial austempering in a salt bath at 340° for 420 sec (for steel 60) and 1380 sec (for steel 80), final cooling in water, and electrotempering at 430–460° for as long as 20 sec.